In order for rose blossoms to pile up in opulent abundance, healthy, vital foliage is essential. If the leaves are healthy, the entire metabolic process runs smoothly. Photosynthesis proceeds in a regulated manner. Nutrients and water get to where the buds thrive and develop into royal blooms. All the more devastating for the rose gardener when the leaves present themselves with brown spots. This symptom indicates an infection with rose rust, a dreaded fungal disease on the queen of flowers. Instead of throwing in the towel right away, read here which methods of combating the disease have good prospects of healing.
Table of Contents
The symptoms
The top priority for successfully combating rose rust is an unambiguous diagnosis. Only when you are confronted with this rose disease with a probability bordering on certainty can the various methods of healing and prevention lead to success. We have therefore compiled an overview of the most important symptoms for you below:
- Timeframe for infestation: mid-April to late July
- Pinhead-sized, dark yellow to reddish-brown spots develop on the upper side of the leaves
- Dark orange-red spots appear on the undersides of the leaves, which turn brown and black
- In the further course, the leaves yellow and fall off prematurely
The brown to black pustules are the spore deposits of the fungi, which over time release thousands upon thousands of individual spores into the environment. In this way, the infection tries to spread to other roses and other plants in the garden. This disease is therefore classified as highly contagious.
combat
If you notice the first symptoms of rose rust during your inspection tour of the rose garden, immediate action is required. The best chance of saving the infested rose is in the early stages of infestation. First, collect fallen leaves so that no more spores can spread from here. Then treat the diseased flower with one of the following preparations:
Compo Duaxo Rosen-Pilzfrei
Based on the active ingredient difenoconazole, the agent acts as a fully systemic fungicide concentrate. Properly used, the agent not only puts an end to rose rust, but also acts against blackspot, powdery mildew and other fungal diseases.
Price for 50 ml concentrate: approx. 8.50 euros
Compo Duaxo Rose-fungus-free Spray
Fix and ready for immediate use as a spray, this agent requires no effort for the preparation in the pressure sprayer. Due to the fine spray mist, this product is well suited for combating rose rust in closed rooms, such as the office, conservatory or on the balcony.
Price for 400 ml spray bottle: approx. 10 euros
Celaflor Rosen-Filzfrei Saprol
Used in the early stages, this preparation offers good prospects of success against rose rust and other fungal diseases on ornamental plants. The dominant active ingredient, triticonazole, is considered harmless to bees and other beneficial insects such as ladybugs or predatory mites. Dissolved in water according to the dosage instructions, the agent is repeatedly applied to the upper and lower sides of the leaves affected with brown spots at intervals of no more than 10 days.
Price for 100 ml (enough for 10 liters of ready-to-use solution): approx. 11 euros
Celaflor Pilzfrei Ectivo
Originally developed to combat fungal infections in stone fruit, it quickly became clear that this remedy also puts an end to rose rust. The key ingredient here is myclobutanil, which is kind to beneficial insects and acts as a broad spectrum fungicide. However, the application is limited to temperatures below 25 degrees Celsius, which can become a problem during the peak rose rust season in summer.
Price for 100 ml: approx. 10 euros
Bayer Garten Rose-fungus-free Baymat
The innovative new development scores with an effect that lasts up to 3 weeks against rose rust and other diseases typical of roses. In addition, the preparation contains caring components, which at the same time ensure a rich green color of the leaves and a beautiful shine, which quickly makes you forget the unsightly brown spots.
Price for 100 ml (enough for 25 liters of ready-to-use solution): approx. 10 euros
Specialist retailers offer combination preparations for particularly troubled rose cultures, which are both plagued by rose rust and sucking pests. These can be used individually or together to combat fungal infections and lice in one go. Of course, environmentally conscious hobby gardeners will only opt for this chemical ‘steam hammer method’ if there is maximum infestation pressure.
Tip: The Federal Office for Consumer Protection and Food Safety (BVL) runs an online database with all approved pesticides. Interested hobby gardeners can find up-to-date information here about which preparations can be used to prevent rose rust in the home garden. Information on the Federal Office of Consumer Protection and Food Safety (BVL)
Proper use for maximum success
In order for the fungicides presented to develop their full effect, it is important that they are used professionally. Read the instructions for use carefully, because they contain all the details regarding when to use and the dosage. Preparations that are not ready for use are to be mixed with water exactly according to the instructions in order to avoid overdosing. Different concentrations apply to the application with the watering can than when the pressure sprayer is used. You avoid this risk by purchasing an AF product that is already mixed and ready to use. Once the fungicide is ready, put on protective clothing to avoid exposure to the chemical ingredients. Long pants, long-sleeved shirts, gloves, sturdy shoes and safety goggles are the top gardener’s duty, if chemical agents are used to combat rose rust. This is how the further application works:
- dry, windless weather with moderate temperatures
- Best time early morning or late evening
- No rain is forecast for the next few days
- Mix only as much spray mixture as is required for one application
The rose rust control agent is always sprayed dripping wet on the upper and lower sides of the foliage. Be sure to avoid eating, drinking and smoking while doing this work. Keep children and pets out of reach of treated roses for the day and the following day. Finally, all tools and clothing are thoroughly cleaned. Fungicide residue should not be disposed of down the drain, toilet or any body of water.
home remedies
If you keep a watchful eye on your roses and check the leaves for brown spots every day, you can use environmentally friendly home remedies to counteract this at the first sign of rose rust. In particular, in the home garden managed in a way that is close to nature, there are at least hopeful prospects of being able to avoid resorting to chemicals. The focus is on the following two natural mixtures that have proven themselves in the fight against stubborn fungal infections.
Horsetail broth
The high silicic acid content in field horsetail has a strengthening effect on the plant cells of rose leaves and thus protects against fungal spores. It is important to note that you only use the sterile, green stalks of the Equisetum arvense to make the broth. The brown shoots with the terminal spore spikes that have sprout from the rootstock in the weeks before are not suitable for biological control of rose rust. The collection period extends from May to July. The following recipe has proven itself:
- Soak 1 kg of fresh or 150 g of dried plant parts in 10 liters of water
- After 24 hours, simmer the mixture on a low flame for 60 minutes
- Put a lid on and let cool
Dilute in a ratio of 1:10 and spray repeatedly onto the rose petals. Strengthening affects the mixture if you add nettle manure. If the troubled rose is not only struggling with rust but also with aphids, add 15 ml of pure soft soap to one liter of the broth to kill two birds with one stone.
vermouth
Wormwood is on par with field horsetail when it comes to effectiveness against rose rust. Valuable ingredients such as thujone, flavonoids, tannins and essential oils keep the fungal spores under control. The recipe and production are similar to horsetail broth. However, the finished broth should be covered in a sunny location for 3-4 days before it is applied diluted.
preventive measures
As part of the care work in the rose bed, you can effectively prevent an infestation with rose rust. The most important measures at a glance:
Pruning back prunes
your rose bushes in early spring. Critical parts of the plant in which the cunning fungal spores could have overwintered are automatically removed. Make each cut just above an outward facing eye and do not leave clippings in the bed. At the same time, the plant is thoroughly thinned out so that light and air can reach all regions again. In the case of bedding and hybrid tea roses, cut back again in summer down to the second leaf below the withered flower.
Fertilize properly
Avoid fertilizing roses with an emphasis on nitrogen. The queen of flowers reacts much better when supplied with potassium. Special rose fertilizers from specialist shops are composed accordingly. If you prefer organic fertilization, compost manure, wood ash and composted chicken manure can be considered for the nutrient supply.
Do not water overhead
Since the fungal spores settle and spread particularly quickly on moist leaves, roses should not be sprinkled with water for the water supply. Give the irrigation water directly from the spout of the pitcher to the roots.
Dispose of leaves
The fungal spores of rose rust prefer to overwinter on the leaves. Therefore, do not leave the fallen rose petals in the bed. If in doubt, these should not be disposed of in the compost, but in the household waste.
Conclusion
If brown spots spread out on rose leaves, this does not necessarily have to be the end of the dream of a wonderful rose blossom. If effective fungicides from specialist shops are used at the first symptoms, you are not lost in the fight against the fungal infection. If all safety precautions are applied in the right dosage, the rose can be saved. Anyone who is reluctant to use chemical preparations and reacts to the first pinhead-sized pustules on the leaves can experiment with combating them with wormwood or horsetail broth.
